Industrial Injection LB7 Duramax Screw-In Injector Cups Photo Gallery

Don’t Get Screwed

Photo 2/16 | 001 Industrian Injection Duramax Screw In Injector Cups | Despite being offered as a kit with the injector cups and tap cutting fluid, Industrial Injection’s screw-in injector cups are not intended to be a do-it-yourself project. However, if you find yourself mechanically inclined enough and willing to take the risk, it is certainly not an impossible task to perform at home. In addition to the kit, you’ll also need a tap handle, thread locking compound, brake cleaner, and injector cup O-rings.

Photo 3/16 | 002 Industrian Injection Duramax Screw In Injector Cups | Seen here is one of Industrial Injection’s screw-in cups next to a well-used factory cup. You’ll notice the main difference is the threaded section on the tip of the cup. Industrial’s cups are custom made with this in mind; they are not simply threaded factory cups.

Photo 5/16 | 004 Industrian Injection Duramax Screw In Injector Cups | We started our project with a set of freshly rebuilt heads from Freedom Racing Engines. If you’re planning to install these in used heads, a thorough cleaning is in order before beginning. The focus of our work is here, where the injector cup meets the combustion chamber.

Photo 6/16 | 005 Industrian Injection Duramax Screw In Injector Cups | Included with the kit is a bottle of Tap Magic cutting fluid. This oil is specifically formulated for tapping aluminum. The tap needs to be kept well lubricated during the entire process, as it will ensure a clean and easy cut.

Photo 7/16 | 006 Industrian Injection Duramax Screw In Injector Cups | The included tap has a pilot that fits snuggly into the injector cup bore. This is the most critical part of the operation, as the tap must start threading perfectly straight. If the new threads are cut at an angle, the injector cups may not seat properly in the head.

Photo 8/16 | 007 Industrian Injection Duramax Screw In Injector Cups | It’s important to go slow and keep the tap properly lubricated during the cutting process. If at any point it gets difficult to turn the tap, stop and add more lube. It’s also important not to reverse the tap. When the threads are cut, simply release the tap and remove it from the opposite side of the head.

Photo 9/16 | 008 Industrian Injection Duramax Screw In Injector Cups | After cutting the threads, the area needs to be cleaned of oil and debris. Brake cleaner does a fantastic job of blasting away all the unwanted crud. You’ll also need to flip the head over and clean all the aluminum shavings out of it in much the same manner.

Photo 10/16 | 009 Industrian Injection Duramax Screw In Injector Cups | What you’re left with is perfectly cut threads ready to accept the new injector cups. The downside, if there is one, is that this head will now only accept screw-in injector cups; there is no going back.

Photo 11/16 | 010 Industrian Injection Duramax Screw In Injector Cups | Much like standard injector cups, Industrial’s screw-in units require a copious amount of thread locking compound to be applied to the newly threaded area as well as the lower mating surface of the cup. In this regard, there’s no such thing as too much, so go ahead and lay it on thick.

Photo 12/16 | 011 Industrian Injection Duramax Screw In Injector Cups | Before inserting the cups, thread locker should be applied to the threads on the head. We found a simple cotton swab to be the easiest manner of application.

Photo 13/16 | 012 Industrian Injection Duramax Screw In Injector Cups | Next, the O-rings are installed on the injector cups. These need to be oiled along with the bore into which the cups will be inserted in order to ensure a smooth entry and no damage to the seals. Industrial doesn’t provide O-rings with the kit, but they can be purchased separately and are inexpensive. Don’t try and reuse old O-rings.

Photo 14/16 | 013 Industrian Injection Duramax Screw In Injector Cups | Once everything is in order, the cups can be gently lowered into the heads from the topside.

Photo 15/16 | 014 Industrian Injection Duramax Screw In Injector Cups | A special adapter is included with the kit to tighten the new cups. Industrial recommends torquing the cups to 35 ft-lb after they bottom out. Take care during this step, as the tool for tightening the cups is delicate, and the tiny pins can be easily damaged if the tool comes out of alignment.

Photo 16/16 | 015 Industrian Injection Duramax Screw In Injector Cups | When all is said and done, the process takes only a couple of hours from start to finish—as long as the heads are already removed from the engine. If installed correctly, these new injector cups will last a lifetime and should never need to be removed. However, if for some reason they do need to come out, they can be unthreaded the same way they went in and reused indefinitely.